Acetogenic microorganisms can produce ethanol from carbon monoxide (CO) through fermentation of gaseous substrates. Fermentations using anaerobic microorganisms from the genus Clostridium produce ethanol and other useful products. For example, U.S. Pat. No. 5,173,429 describes Clostridium ljungdahlii ATCC No. 49587, an anaerobic microorganism that produces ethanol and acetate from synthesis gas. U.S. Pat. No. 5,807,722 describes a method and apparatus for converting waste gases into organic acids and alcohols using Clostridium ljungdahlii ATCC No. 55380. U.S. Pat. No. 6,136,577 describes a method and apparatus for converting waste gases into ethanol using Clostridium ljungdahlii ATCC No. 55988 and 55989.
Acetogenic microorganisms may be grown to produce ethanol from syngas that includes carbon monoxide. The growth process may involve culturing the acetogenic bacteria on increasing amounts of CO over time. High or low levels of CO in the fermentation may result in lower productivity.
Monitoring and control of fermentation condition are important for improving productivity during fermentation of gaseous substrates. Dissolved CO in a fermentation medium is typically a calculated number determined by using Henry's Law. Direct and real time measurement of dissolved CO concentrations in a fermentation medium would be effective for enhancing monitoring and control of the fermentation and enhancing productivity levels.